In the transmission of data over an analogue channel from an analogue modem to a digital modem the data in general is converted to a series of constellation points of a constellation, and the constellation points are then transmitted through the analogue channel. However, in general analogue channels suffer from a relatively high degree of noise and/or other impairments which distort the constellation points during transmission, thus leading to inaccuracies of decoding the received constellation points. This, in general, is undesirable.
There is therefore a need for a method and apparatus for transmitting data from an analogue modem to a digital modem through an analogue channel which minimises the effect of noise and/or other impairment in the analogue channel on the signals being transmitted through the analogue channel.
The present invention is directed towards providing such a method and apparatus.